Multifilament-responsive thread break detector



Aug. 18, 1953 c. B. HAYES ,648,961

MULTIF'ILAMENT RESPONSIVE THREAD BREAK DETECTOR Filed July 31, 1951 2Sheets-Sheet 1 TEXTILE OPERATION Z6 26 8 X INVENTOR.

CLYDE B. HAYES ATTORNEY Aug. 18, 1953 Fiied July 31, 1951 c. B. HAYES2,648,961

MULTIFILAMENT RESPONSIVE' THREAD BREAK.DETECTOR 2 Sheets-Sheet 2 (3* r!h &@ sl

"' lllll IHH' "villi "'HHIIIH' INSULATION INVENTOR. CLYDE B. HAYESATTORNEY Patented Aug. 18, 1953 MULTIFIIJAMENT-RESPONSIVE THREAD BREAKDETECTOR Glyde'B. Hayes,,Wolctt, Conn., assignor of twothirds to HarryFleisher, Water-town, Conn., Max Doft, Cedarhurst, N. Y.,, and HarleyWilson, Watertown, Conn.

Application July '31, 1951", SerialNo. 239,448

Claims. 1

This invention relates to. a multi-filament-responsive thread breakdetector for'textile. machines.

By way of example the invention will be described herein with respect toa tricot knitting machine. However, it.is to be understood that thisspecific form of the invention only is to be considered as illustrativeand the invention is nottobe deemed as limited thereby except as and tothe extent to which features of such embodiment are pointed out belowand are incorporated intheappended claims.

In a machine suchas a tricot machine wherein a very large number(thousands) of threadsisimultaneously are knitted,.warped, reeled or thelike, it is time-consuming, expensive, cumbersome and diflicult to haveav different stop-motion device associated with each thread. Hence ithas been proposed to employ amulti-filamentresponsive stop-motion devicewhich is so constructed as to be sensitive to the breakage of any one ofa large number of threads for. example, any one of a largegroup ofthreads in a tricot machine.

In general these multi-filament-responsive thread break detectorseitherconstitute asingle element which is depressedupon.thetautening ofa broken thread, or a pair of electrodeswhichare bridged by a brokenthread which had been rendered conductive by impregnation. These twotypes of thread break detectors are comparatively. slow in operation,cumbersome, complex and not sufficiently delicate for reliable operationin conjunction with very-fine yarns.

It is an object of the present invention toprovide amulti-filament-responsive thread breakdetector which is not subject tothe .foregoingdrawbacks.

More specifically it-:is .anobjectof the invention to provide a simple,.positivesacting, efficient, rapid, sensitive, foolproofand durabledetector of the character described.

Other objects of. the invention. will-in:par.ti:be obvious and in partwill. be pointed; out. herein.- after.

The invention accordingly consists in the: fea tures of construction,combinations of. elements and arrangements of parts which will beexemplified in the devicehereinafterdescribedi and of whichthe scope ofapplication will be: indicated in the appended claims.

Inthe accompanying drawings in which is shown oneof the various possibleembodiments =of the invention,

Fig. l is-a front-to-back sectional, and" partly schematic, view of atextile machine employing a multi-filament-responsive thread breakdetector constructed-in accordance with the presentinvention;

Fig. 2 is a fragmentary side view of said detector;

Fig. 3is-a fragmentary top view of the detector;

Fig. 4 is an enlarged fragmentary sectional view taken substantiallyalong the line 44 of Fig. 3.;

Figs. 5 and 6 are enlarged sectional views taken substantially along thelines 55 and 6-6,,respectively of Fig. 4;

Fig. '7 is an enlarged sectional view takensubstantially along the line1-1 of Fig. 3; and

Fig. 8 is an enlarged sectional viewtaken sub stantially along the line88 of Fig. 2.

In general the invention is carried out by providing a detectorincluding an extremely light sensing element which is mounted on acarrier that moves the element along a path of travel beheath andtransverse to the path of threads fed to a multi-filament textileoperation. Said element is so mountedon the carrier as to be shiftablein a direction opposite to the direction of movement of the carrierwhereby when a broken or slack thread falls in front of said element theimpediment to forward movement of the element offered by the thread issufficient to cause the element to be shifted relative to the carrier.Such movement of the element is arranged to energize a circuit whichstops the textile operation. Desirably, the. circuit is energized withthe aid of circuit elements which are bridged by the sensing elementupon shifting-thereof, said. circuit elements further constitutingameans for holding .a broken or slack thread at a suitable level in. thepath of travel of the sensing element.

Referring now in detail to the drawingsthe reference numeral illdenotesaconventional textile;machine, such for instance as atricot ma-- chine,which-is constructed to operatesimultaxneously upon alarge number. ofthreads. Said machine typically includes one or moredriven warp beams 12from which a. large number of threads. l4 extend. Said threads runbeneath a whip roll [6 and over a .tensionbar. [8 to a, mechanism.2.0which performs the textile. operation, e: g. knitting. Optionally, asley bar. iliis. lo;- cated. adj acent: the region where. broken or.slack threads-are tobe detected; here shownas between the whip roll-andtension ban.

The machine H] has. associated therewitha multiefilamenteresponsivethread break detector 2.4" whose construction and operation is thesubject' of the present invention; Said detector is 3 elongated and islocated beneath the path of travel of all the threads M with thelongitudinal axis of the detector transverse to and beneath thedirection in which the threads generally extend.

The detector includes a long narrow rigid stringer bar 26 which isattached to stationary parts of the machine in such position that thebar is beneath and extends at right angles to all the threads l4, saidbar being long enough for its ends to project to both sides of the pathcovered by all the threads. Mounted on the stringer bar is an endlessflexible carrier 28, such for example as a narrow thin steel belt,having an upper and a lower reach. The upper reach is disposed above theupper surface of the stringer bar and the lower reach extends beneaththe lower surface of said bar. The belt is supported for movement withits reaches located as aforesaid by an idler flanged pulley 30 at oneend of the stringer bar and by a flanged rubber-faced driving wheel 32at the opposite end of the bar. The pulley 30 is pournalled inadjustable side plates 34 and the wheel 32 in side plates 35.

A gear 38 rotatable with the driving wheel 32 is in mesh with a pinion40 driven by a suitable prime mover such for example as an electricmotor (not shown). The electric motor continuously moves the upper reachof the belt in a direction indicated by the arrow A. Said belt ismaintained in proximity to the upper and lower faces of the stringer barby guides 42 constituting angle-shaped brackets having legs overhangingthe longitudinal edges of the belt.

A pair of electrically non-conductive blocks 44 are attached to thestringer bar near one end thereof on opposite sides of the bar. Asimilar pair of electrically non-conductive blocks 45 are attached inlike fashion to the bar near its opposite end. The distance from onepair of blocks to the other exceeds the width 0. (Fig. 2) of the pathtraversed by all of a group of threads whose breakage is to be sensed bythe detector 24, the bar 26 being so located that one pair of blocks 44is beyond one side of said path and the other pair of blocks 46 isbeyond the other side of said path.

The blocks project above the upper surface of the bar and are providedwith suitable means, such for example as posts 48, to support a pair ofparallel, elongated, slender, electrically conductive rods The rods liein a common horizontal plane and desirably are spaced symmetrically withrespect to the longitudinal axis of the stringer bar. The upper sides ofthe rods are bare, i. e. uninsulated, so that if an electricallyconductive element is laid athwart the rods, current will pass from onerod to the other. The ends of each rod are supported by the posts 48that are located on the same side of the longitudinal axis of thestringer bar as the rod so that the rods define an open-ended longnarrow space (see Fig. 3).

The outer surface of the steel belt carries a set of sensing elements52. Said elements are uniformly spaced apart along the length of thebelt and are aligned paralled to the longitudinal axis of the bar. Inthe preferred form of the invention the sensin elements are so locatedon the belt that the centers of said elements travel along a linecoincident with the center of the space between the rods 50.

The longitudinal spacing between the sensing elements is determined bythe speed of travel of the belt and by the rapidity with which it isdesired to have a broken or slack thread sensed. Highly satisfactoryresults have been secured where the sensing elements are spaced apartlongitudinally about six inches and the speed of travel of the belt isten feet a minute. This arrangement insures the passage of a sensingelement beneath any given thread once every three seconds.

Each sensing element comprises a shank 54 having a transversely extendinelectrically conductive head 56 at its distal end. Said head may be ofany suitable shape and preferably includes upwardly inclined portionsextending outwardly from, and to both sides of, the distal end of theshank. In the embodiment of the invention here shown the overalltransverse dimension of the head must exceed the space between the rods50. The distal end of the shank 54 and center of the head 56 arecentrally located with respect to the rods 50.

Means is included to mount the proximal end of each shank 54 forrotation about a horizontal axis transverse to the path of travel of theshanks. Said means simply may comprise a laterally offset arm 58 formedat the lower end of the shank and rotatable in a horizontal transversebore 50 formed in a link 62. It is desirable for the bore to be somewhatlarger in diameter than the diameter of the arm and for the length ofthe bore to be slightly less than the length of the arms in order topermit a limited sidewise shifting and rocking play of the head 56 ofthe sensing element. The reason for this shortly will be apparent.

In accordance with a critcal feature of the invention said sensingelement, i. e. a shank 54 and head 56, is extremely lightso light thateven a fine thread lying in the path of travel of the shank will soimpede movement of the sensin element that it will swing about itshorizontal axis of rotation on the link. To this end the sensing elementis fabricated from extremely thin metal wire and has an almostnegligible weight. A typical sensing element of the shape shown in theaccompanying drawings is about one inch high and has a weight of aboutonetenth of a grain, e. g. 0.0085 gram. The illustrated diameter of thewire is exaggerated for the purpose of illustration.

Each link 62 is pivotally secured by a horizontal pin 64 to a differentblock 66 that is rigidly attached, as by welding, to the outer surfaceof the steel belt 28. The link is considerably heavier than the sensingelement 52 so that, regardless of the position of said sensing element,the link will lie flat when it is on the upper reach of the belt andwill dangle from the block 68 (see Fig. 2) when it is on the lower reachof the belt.

The link is provided with an upstanding support 68 against which theshank 54 of the sensing element rests when said sensing element is inoperative, i. e. unactuated, position, the same being indicated by thereference character I) on the upper reach. The support is so locatedwith respect to the pivotal axis of rotation of the sensing element thatin such unactuated position the center of gravity of the sensing elementis forward of said axis, forward denoting in the direction of movementof the upper reach of the belt indicated by the arrow A. Thus thesensing element when in unactuated position is in stable equilibrium,being pivotally mounted at its proximal end and having its shankinclined forwardly and resting intermediate the ends thereof on thesupport 68. The shank is sufliciently long so that acme-oer 5 when" thesensing element is in unactuatedposition its transversely elongated head56 is above and' out of contact with the rods 50.

If anythread I4 slackens or is broken it will drop on the detector andwill lie on and athwart the rods 50 in the path of travel of the sensingelements (see the dotted line position of a broken thread in Fig. 1).Upon reachingsucha loose thread a sensing element because of itsextremely lightweight will'be-impeded and thereby caused to swing aboutits pivot on the link in a. rear warddirection (opposite to thedirection indicated by the arrow A). As the sensing element swingsrearwardly it will quickly reach a position in which its center ofgravity is directly over its pivot. Thereafter the sensing element willfall under the influence of gravity and/or the further. impeding actionof the loose thread until the head-58 engages the rods 5i! (positionindicat'ed-by dot-and-dash Zines in Fig. 2) thereby forming an electricconnection between them. Inorder for the loose thread to exert maximumtorque on a sensing element the upper sides of the rods are at a levelslightly belowthe distal end'of a shank in actuated position.

The rods are series-connected in an electric sensitive relay circuit(not shown), the energizationof which by bridging the rods with aconductor= will operate a device for de-energizing the motor that drivesthe machine It.

Although it is within the scope of the invention tohave the sensingelements travel along the return, i. e. idle, reach, in an erectposition leaning in the direction of travel but too low to be engaged bya loose thread, in the detector shown herein the sensing elementstraverse the idle reach in an inverted position d as shown in Fig. 2.

When the sensing elements pass around the idler pulley 30 and therebyare erected, they will bedisposed in a position e (Figs. 2 and 4) inwhich their heads 56 would engage the rods 59. It is essential to shiftthe sensing elements from such a'position e to their unactuated-positionb and suitable means is provided for this purpose. Such'means comprisesa cam follower 10 on each link (see Figs. 3 and 5), the sameconstituting a pin extending transversely away from both sides of'thelink. Said cam follower cooperates with a cam 72 including a pair of camelements l4, l6 one located on each side of the stringer bar between theidler pulley 38 and the blocks 46. Each cam element consists of a trackcam 18 (Fig. 4) having a central raised lobe 80, a low entrance and alow exit 86.

After traversing the idler pulley 30 an erected sensing element is inposition 6 (Figs. 2 and 4) in which its shank 54 is erect but rests onthe pin 10 and leansin a rearward direction. The entrances=84 to the camtracks 18 are at the level of'the cam follower with the sensing elementin position e. As the moving belt 28 carries the sensing element betweenthe two cam elements 14, 1B the opposite ends of the follower pin 10ride into the entrance of the cam tracks. Furthermovement of the carrierbelt will lift the cam follower and link, causing the latter to rotatein a counterclockwise direction as viewed in Fig. 4.- with respect tothe block 55. It will be observed that since at this time the shank ofthesensing elementis resting on the follower, upward movementof thefollower causes the sensing element to-rotate with the link about thepivot 64. The lobe '80 is of such height that it will lift the linksufiicienly to oscillate the sensing element to a position f (Fig, 4) inwhich its centerof gravity 6. is forward of the axis ofpivotalmovementof the sensing'element with respect to its associated link. Whenthis position is reached the sensing element will fall into aconditionof stable equilibriumin which its shank restsagainst the support 68.Thereafter the cam follower willmove down the descending part of the camtracks: to restore-the link to its normal'horizontal position b lyingflat on the steel belt. The sensing'element now moves betweenthe tworods 50 and is ready to-detect the presence of a broken or slack thread.

To make certain that the cam follower enters the-cam tracks, both camelements are fashioned with upwardly inclined and rearwardly extendinglips 88 which terminate at the upper edges of. the entrances 84 to thecam tracks. If, due to.- the presence of dirt or other foreign materialon-the beltbeneath a link, the linkapproaches the cam elements in raisedposition, as shown for example by position 9 in Fig; 4, the cam followerT0: will engage the undersurfaces of the lipsBB andhe forced into theentrances 84' of the cam tracks. If a cam follower does not ride throughthe cam tracks a-sensing element might approach theen-itrance-to therods Eifwhile still in the 6 position and thereby jam and distortagainst the rods.

To facilitate contact of the head? 56 of the sensing element with bothrods Eil'at the. time that the sensing element drops on the rods, theedges of the sensing element which engagesaid rods are sloped downtowards the distal end. of the shank 54 as already mentioned.Thiszarrangement enables the head to center itselfbetween the rods andthus ensures engagement with both rods. It is for such purpose that the:pivotal mounting of the sensing element .on the-link. is so constructedas to permit sidewise play thereof.

When a sensingelement drops into engagement with the two rods, thegravitational force which holds the head of the element against therodsgis extremely light. Hence it is desirable to. ensure that thecontact surfacesof the rods are kept clean.

Accordingly a wiper 90' is mountedon the belt in line with the sensingelements. The wiper is secured to ablock 92 that is rigidly connected tothe belt, the wiper being attached to said block by a pin 94 whichpermits rotation" of the wiper about a horizontal axis. Likethe-sensingv elements, the pivotal mounting of 'the wiper permits someside play and rocking to ensure centering of thewiper between the rods.The wiper is com,- posed of rubber or a synthetic elastomeric substanceand includes a shank 96 with a head98 whose sides slope upwardly andoutward from the distal end of the shank. The sides of the head ride onthe-upper sides of :the rods 50 and by con-.- stant scraping action keepthe contact surfacesof the rods clean.

The width of the wiper head exceeds therspace between the rods 50 but isless thanthespace between the cam tracks 18 so that it is not liftedthereby. When the wiper approaches the blocks 46 itshead is slightlybelow the level'ofthe rods being supported in such position by astepxlllil on the block-92. In order to raise the wiper head one of theblocks 46 is formed'with a ramp, 1. e. a cam surface I02, along whichthe wiper rides and is lifted to the level of'the rods.

It thus will be seen that there is provided a device which achieves allthe objects of the invention and is well adapted to meet the conditionsof practical use.

As: various possible embodiments might be 7 made of the above invention,and as various changes might be made in the embodiment above set forth,it is to be understood that all matter herein described, or shown in theaccompanying drawings, is to be interpreted as illustrative and not in alimiting sense.

Having thus described the invention, there is claimed as new and desiredto be secured by Letters Patent:

1. A multi-fllament-responsive thread break detector comprising anextremely light sensing element, a carrier, means to mount said carrierfor movement transversely beneath the path of a largenumber of threads,means to mount said element on said carrier for movement with respect tosaid carrier between an unactuated position and an actuated position andin a direction having a substantial component parallel to the directionof movement of said carrier, a pair of elongated members disposed onopposite sides of the path of travel of said element slightly below thedistal end thereof, the unactuated position of said element leading theactuated position thereof and said element normally being disposed inunactuated position whereby when a slack thread falls in the path oftravel of said element it will impede motion of said element and causesaid element to shift from unactuated to actuated position, and electriccircuit closing means rendered effective upon movement of said sensingelement to actuated position.

2. A multifilament-responsive thread break detector comprising anextremely light sensing element, a carrier, means to mount said carrierfor movement transversely beneath the path of a large number of threads,means to mount said element on said carrier for movement with respect tosaid carrier between a high unactuated position and a low actuatedposition and in a direction of movement of said carrier, the unactuatedposition of said element leading the actuated position thereof and saidelement normally being disposed in unactuated position whereby when aslack thread falls in the path of travel of said element it will impedemotion of said element and cause said element to shift from unactuatedto actuated position, and a pair of electrically conductive rods lyingon opposite sides of the path of travel of said element and disposed tobe engaged by said element when the same is in its low actuated positionwhereby to constitute electric circuit closing means which is renderedeffective upon movement of said sensing element to actuated position.

3. A multi-fllament-responsive thread break detector comprising anendless flexible belt, a pair of horizontally journalled pulleyssupporting said belt with an upper reach extending transversely beneaththe path of a large number of threads and a lower reach, an aligned setof extremely light sensing elements, means to mount each element on saidbelt for pivotal movement about a horizontal axis between a highunactuated position and a low actuated position, each said pivotal axisbeing transverse to the direction of movement of said belt, theunactuated position of each element leading the actuated positionthereof and each element normally being disposed in unactuated positionon the upper reach whereby when a slack thread falls in the path oftravel of any element it will impede motion of said element and causesaid element to shift from unactuated to actuated position, and a pairof electrically conductive rods lying on opposite sides of the path oftravel of said elements on the tive upon movement of any sensing elementto actuated position.

4. A multi-fllament-responsive thread break detector comprising anendless flexible belt, a pair of horizontally journalled pulleyssupporting said belt with an upper reach extending transversely beneaththe path of a large number of threads and a lower reach, an aligned setof extremely light sensing elements, means to mount each element on saidbelt for pivotal movement about a horizontal axis between a highunactuated position and a low actuated position, each said pivotal axisbeing transverse to the direction of movement of said belt, theunactuated position of each element leading the actuated positionthereof and each element normally being disposed in unactuated positionon the upper reach whereby when a slack thread falls in the path oftravel of any element it will impede motion of said element and causesaid element to shift from unactuated to actuated position, a pair ofelectrically conductive rods lying on opposite sides of the path oftravel of said elements on the upper reach, said rods being disposed tobe contacted by any element when the same falls into actuated positionwhereby to constitute an electric circuit closing means which isrendered eifective upon movement of any sensing element to actuatedposition, said elements falling to actuated position as they move arounda pulley from the lower to the upper reach, and means to shift eachelement from actuated to unactuated position between said pulley and therods.

5. A multi-filament-responsive thread break detector comprising anendless flexible belt, a pair of horizontally journalled pulleyssupporting said belt with an upper reach extending transversely beneaththe path of a large number of threads and a lower reach, an aligned setof extremely light sensing elements, means to mount each element on saidbelt for pivotal movement about a horizontal axis between a highunactuated position and a low actuated position, each said pivotal axisbeing transverse to the direction of movement of said belt, theunactuated position of each element leading the actuated positionthereof and each element normally being disposed in unactuated positionon the upper reach whereby when a slack thread falls in the path oftravel of any element it will impede motion of said element and causesaid element to shift from unactuated to actuated position, a pair ofelectrically conductive rods lying on opposite sides of the path oftravel of said elements on the upper reach, said rods being disposed tobe contacted by any element when the same falls into actuated positionwhereby to constitute an electric circuit closing means which isrendered effective upon movement of any sensing element to actuatedposition, said elements falling to actuated position as they move arounda pulley from the lower to the upper reach, and cam and follower meansto shift each element from actuated to unactuated position between saidpulley and the rods.

6. A multi-filament-responsive thread break detector comprising anendless flexible belt, a pair of horizontally journalled pulleyssupporting said belt with an upper reach extending transversely beneaththe path of a large number of threads and a lower reach, an aligned setof extremely light sensing elements, means to mount each element on saidbelt for loose pivotal movement about a horizontal axis between a highunactuated position and a low actuated position, each said pivotal axisbeing transverse to the direction of movement of said belt, theunactuated position of each element leading the actuated positionthereof and each element normally being disposed in unactuated positionon the upper reach whereby when a slack thread falls in the path oftravel of any element it will impede motion of said element and causesaid element to shift from unactuated to actuated position, and a pairof electrically conductive rods lying on opposite sides of the path oftravel of said elements on the upper reach, said rods being disposed tobe contacted by any element when the same falls into actuated positionwhereby to constitute an electric circuit closing means which isrendered effective upon movement of any sensing element to actuatedposition.

7-. A multi-filament-responsive thread break detector comprising anendless flexible belt, a pair of horizontally journalled pulleyssupporting said belt to provide an upper reach extending transverselybeneath the path of a large number of threads and a lower reach, powermeans to turn one of said pulleys, an aligned set of extremely lightsensing elements, each of said ele ments including a shank having a headat its distal end and means to pivotally secure the proximal end of saidshank to said belt for movement about a horizontal axis transverse inthe direction of movement of the belt, a set or supports carried by thebelt, each support being associated with a difierent sensing element andarranged to have the shank of the element rest thereon when the shank ison the upper reach and is inclined in the direction of the movement ofthe belt, the center of gravity of each sensing element in such positionbeing forward of its associated horizontal axis, a pair of electricallyconductive rods lying on opposite sides of the path of travel of saidelements, the transverse dimension or the head of each element exceedingthe space between said rods whereby when a slack thread falls across therods it will impede motion of an element and cause said element to beswung about its axis of povital movement and fall upon said rods, saidrods and element constient link, means to pivotally connect each of saidlinks to its associated block for movement rela tive thereto about ahorizontal axis transverse to the direction of movement of the belt, asupport carried by each link, a transversely extending follower carriedby each link, an extremely light sensing element pivotally connected toeach link for rotation relative thereto about a horizontal axistransverse to the direction of movement of the belt, each sensingelement including a shank and a head, said shank being pivotal between aposition in which it rests on the support and a position in which itrests on the cam follower, said shank in its first named position on theupper reach leaning in the direction or" movement of the belt, and inits second-named position leaning in a direction opposite to themovement of the belt, the center of gravity of each sensing element inits first named position on the upper reach being forward of thehorizontal pivotal axis of the sensing element, said links and sensingelements dangling from the belt when on the lower reach, said linkresting on the belt and said sensing element being in its secondnamedposition when the link and sensing ele ment travel around a pulley fromthe lower to the upper reach of the belt, a cam engageable by the camfollower for swinging each link away from the belt shortly after ittravels around said pulley and thereby advancing the center of gravityof the associated sensing element forwardly of the horizontal pivotalaxis of said element, said cam including a portion for returning saidlink to a position resting on the belt with the sensing element in itsfirst-named position, and a pair of electrically conductive rodsdisposed on opposite sides of the path of travel of said sensingelements on the upper reach of the belt whereby when a slack threadfalls on said rods in the path of travel of any element on the upperreach of the belt it will impede movement of said element and cause saidelement to swing about its horizontal pivotal axis toward the secondposition and until it engages said rods, said rods and sensing elementconstituting an electric circuit closing means.

10. A multi-filamcnt-responsive thread break detector as set forth inclaim 9 wherein the cam includes a portion engaging the cam follower ona link and forcing the same toward the belt, if the same is in raisedposition prior to engagement of the cam follower with the liftingportion of the cam.

CLYDE B. HAYES.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 1,970,264 Welch et a1. Aug. 14, 1934 FOREIGN PATENTS NumberCountry Date 570,639 Great Britain July 16, 1945

